A factorization algorithm to compute Pfaffians

Abstract

We describe an explicit algorithm to factorize an even antisymmetric N^2 matrix into triangular and trivial factors. This allows for a straight forward computation of Pfaffians (including their signs) at the cost of N^3/3 flops.

Comments: 6 pages, 1 figure, V2: Minor changes in the text and refs. added, to appear in CPC